Resonant type fiber-optic gyroscope frequency locking device

Abstract

The invention discloses a resonant type fiber-optic gyroscope frequency locking device.The resonant type fiber-optic gyroscope frequency locking device comprises a light source driving module, a narrow linewidth laser source, a Y waveguide modulator, a first modulation module, a polarization maintaining optical fiber resonant cavity, a signal demodulation detection module, a second modulation module, a digital output module and a lithium niobate straight waveguide modulator.A laser works at constant temperature and constant current and in a steady state, frequency stability is good, and frequency noise introduced by frequency modulation of the laser is effectively lowered.Different from a traditional PZT intra-cavity modulation method, no movable part is arranged in the cavity, the effective refractive index is modulated by modulating the magnitude and direction of an electric field applied to lithium niobate waveguides, equivalent cavity length modulation is achieved, and reliability is high.The modulation voltage is low, no redundish external driver is needed, the structure is simple, and the size and power consumption of a gyroscope are easily reduced.The lithium niobate waveguide modulator has a polarization function and achieves a polarization selection effect in the cavity, the intra-cavity polarization extinction ratio is increased, and noise relevant to polarization is effectively restrained.

Description

technical field [0001] The invention relates to a resonant fiber optic gyroscope frequency locking device, which belongs to the technical field of inertial navigation. Background technique [0002] The frequency locking circuit of the resonant fiber optic gyroscope works at the resonant frequency point, and the frequency locking accuracy directly affects the final accuracy of the gyroscope. The traditional frequency locking method follows the resonance frequency of the resonator by adjusting the center frequency of the laser. This modulation process will cause the frequency of the laser to broaden, resulting in a decrease in the resolution of the frequency sweep waveform, which limits the further improvement of the frequency locking accuracy of the gyro. [0003] At the same time, the resonant fiber optic gyroscope is based on the principle of multi-beam interference, using a narrow-linewidth polarized laser as the light source, and the resonator is wound by a polarization-m...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of insufficient precision of the adjustment frequency locking method of the resonant fiber optic gyro laser and the problem that the secondary polarization state of the resonator seriously affects the detection accuracy, and proposes a single-polarization resonant fiber optic gyro frequency locking device

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